Metal is an excellent material to use as it is flashy, classy and elegant in itself, especially, to indirectly express a product's brilliant function and feature and to use to differentiate premium products and product line. However, there are times when metal poses some challenges in communication because of the difference between the image in pictures and the actual product. For instance, products completely covered in gold or silver look quite artificial or too much of the color actually results in lack of luster. On the other hand, mix in a little black to emphasize the sheen of gold or silver and some respond that the image looks different from the actual product. (The images captured by our eyes carry a mixture of more complex distractions and lights than the images.)

 One of the most common ways of expressing metal in photo images is to use a black vertical line right down the middle of the metal part in the image. Of course, there is no black line, but it is what you see when you use reflectors in areas except for where the camera stands to take pictures of the image. We understand that the black line is how metal looks in images by repeated exposure to these images (in magazines, print advertisements, and video media), and that there is no actual black line in the product.

 We have come to understand and agree through repeated exposure that it is a way to express that the material in the image is metal, but at the same time, the familiar black line down the center is somewhat plain and common.

 This is the background to why different brands started to use various character lines to express metals in their own unique ways. It is important to use a consistent way of expressing material texture and shape of containers. In other words, it is an emphasis of the importance of image guidelines. It is better to have customers recognize the unique way of expressing images in line with brand guideline, much like how we have come to agree on a way of expressing metal in images through repeated exposure.

 When the way of expressing material and texture is different in the segmented image and the final produced image for the same product, some provide feedback saying that the images of the same product look different. However, it is effective to have different ways of expression for a segmented image, where the assumption is that the background to the product is white, and the produced image, where image concept is prioritized and harmony with the background is an important factor, even if the images are of the same product. Compared to segmented images, an observer of the image accepts the surroundings reflected on the surface of the product in a produced image. And this reflection is what makes the image natural and in harmony with the background and image concept. Providing a more consistent look and feel across the entire product line is a more effective way of image communication than expressing the entire products in a 'perfect-looking' way.